Turbocompressor jet-propulsion apparatus and adjustable nozzle therefor



P 1953v F. B. HALFORD ET AL 2,653,445

TURBOCOMPRESSOR JET-PROPULSION APPARATUS AND ADJUSTABLE NOZZLE THEREFORFiled.June 19, 1946 4 Sheets-Sheet l A (Am 1M7)! fins/mg (Am [xv-limefins/me) Inventors FRANK B HA F"!! I ERI "a 43141 A t iorneys S p 1953F. B. HALFORD ET AL 2,653,445

TURBOCOMPRESSOR JET-PROPULSION APPARATUS AND ADJUSTABLE NOZZLE THEREFORFiled June 19, 1946 4 Sheets-Sheet 2 A llorneys Sept. 29, 1953 F. a.HALFORD ET AL TURBOCOMPRESSOR JET-PROPULSION APPARATUS AND ADJUSTABLENOZZLE THEREFOR Filed June 19, 1946 4 Sheets-Sheet 3 In ventors" AHorneys p 1953 F. B. HALFORD ET AL 2,653,445

TURBOCOMPRESSOR JET-PROPULSION APPARATUS AND ADJUSTABLE. NOZZLE THEREFORFiled June 19, 1946 4' Sheets-Sheet 4 In ven tors F/i'lA/A a IltFaRp457m 40017- A ttomeys Patented Sept. 29, 1953 TURBOCOMPRESSORJET-PROPULSION APPARATUS AND ADJUSTABLE NOZ- ZLE THEREFOR Frank BernardHalford, Edgware, and Eric $tan-' ley Moult, Hatch End, England,assignors to The De Havilland Aircraft Company Limited, Hatfield,England, a company of Great. Britain Application June 19, 1946, SerialNo. 677,695 In Great Britain May 11, 1945 Section 1, Public Law 690,August 8, 1946 Patent expires Mayj11,.1965

4 Claims. (01. Gil-35.6)

This invention relates to jet propulsion apparatus embodying aturbo-compressor and as. more especially intended for use in aircraft.The invention is applicable to various types of such apparatus in whichit is desirable to vary the propulsive thrust of a jet reaction.

A type of this propulsion apparatus to which the invention is moreparticularly applicable comprises a compressor coaxial with and drivenby a turbine from which it is spaced apart in the axial direction thecompressor delivering air either into a single annular combustionchamber or into a series of separate tubular combustion chambers spacedapart circumferentially in an annular formation around the turbine shaftand between the compressor and the turbine to which the combustionproducts flow and cause its rotation before these gases issue withpropulsive effect from a single nozzle which may either be coaxial withor have its axis inclined to that of the turbine shaft. The object ofthe invention is to provide means whereby the effective exit area of thenozzle through which the gases issue can be varied.

In a given propulsive unit of the type indicated above, a reduction inthe area of the nozzle has the effect of giving increased thrust at theexpense of increased temperature conditions, at a constant speed ofrotation. Hence in a unit which is already operating at its maximumpermissible speed, as limited by centrifugal stresses, reduction in thearea of the nozzle provides a means of giving increased thrust for shortperiods during which the increase in temperature would not be harmful.Again if the temperature of the turbine falls when the aircraft is inflight, as usually occurs at a substantial altitude, the effectivethrust of the jet can be increased by reducing'the nozzle area. f V

It has been proposed to effect variation in the area of these nozzles inone case by the use of a stream-lined body mounted so that it can slidesomewhat as a valve Within a circular nozzle and along its axis. Inanother case where the nozzle has a polygonal orifice the side walls ofthe nozzle have been hinged or made flexible. Such devices beingnecessarily subjected to the full heat of the gases, are liable todistortion and consequent failure to operate.

According to this invention there is combined with the nozzle a sleevewhich surrounds the nozzle from which it may be spaced apart the radia1directionso as to leave an annular passage between the sleeve and thenozzle, and means for extending the length of the sleeve in thedirection of the axis of the nozzle, whereby when thus extended thesleeve by reason of its having a diameter greater than the diameter ofthe nozzle will increase the efiective exit area of the nozzle. Thissleeve formed as a tubular member maybe mounted so that it can slide inthe direction of the axis of the nozzle so as to cause a part of thesleeve to project beyond the nozzle orifice. Alternatively the sleevemay be fixed with one or more tubular members mounted on it so that eachof these members can slide in a telescopic manner on the sleeve or oneach other and produce the effect of an extension of the sleeve with aconsequent increase in the effective exit area of the nozzle. There maybe two or more of these telescopically sliding members and means may beprovided for moving them collectively or separately so that as they havedifferent diameters there may be produced with them the effect ofdifferent diameters of nozzle. With this arrangement the sleeve is notexcessively heated because of the flow of cool air drawn through theannular space between the sleeve and the nozzle so that risk of stickingdue to distortion is minimised. It may also be remarked that a precisefit between the fixed and movable parts in contact, such as the sleeveand the members movable thereon, is not necessary since the passage ofair between them merely adds to the cooling effect as this air flowsthrough and mingles with the main air flow through the sleeve.

The end of the sleeve, if the whole sleeve is adapted for sliding, orthe end of the tubular member which slides on the sleeve, or the end ofthe outermost of a set of telescopic members, may be flared.

If'desired, additional fuel may be injected and burnt in the tai1 pipeleading to the nozzle thereby raising the temperature and velocity ofthe gases issuing from the nozzle. This device is more especially usefulwhen combined with the above described means for varying the effectiveexit diameter of the nozzle.

The accompanying drawings illustrate diagrammatically and by way ofexample various ways in which the invention may be carried out inpractice. In these drawings:

Figure 1 is a longitudinal part sectional plan of a jet propulsionapparatus which illustrates how, in a non-movable nozzle, the effectivearea of the jet nozzle may be increased in a simple manner so as toprovide additional thrust.

Figure 2 is a sectional elevation of the jet nozzle in apparatus as seenin Figure 1 showing one arrangement for varying the effective exit areaof the jet nozzle, the device being here adjusted so as to reduce thediameter of the nozzle.

Figure 3 is a View similar to Figure 2 but showing the device adjustedso as to increase the diameter of the nozzle.

Figure 4 is a view similar to Fig. 2 showing an alternative arrangementof the device as shown in Figures 2 and 3, in which the forward end ofthe fixed sleeve is connected to the nacelle.

Figure 5 is a view similar to Figure 2 showing yet another arrangementin which the forward end of the nozzle is connected to the nacelle.

Figure 6 illustrates by means of alike View an arrangement similar tothat shown in Figure 4 but with the device constructed to enable agreater variation to be effected in the diameter of the jet nozzle.

Figure 7 is again a similar view showing means for introducing fuelwhich is burnt in thenozzle.

Figure 8 is a transverse section'on the line 83 in Figure 7.

Figure 9 illustrates another arrangement of adjustable telescopicmembers for varying the effective exit diameter of the jet nozzle, thememhere being shown in their fully extended positions.

Figure 10 is a view similar to Figure 9 but showing the memberstelescoped inwards so as to reduce the size of the nozzle.

Figure 11 is an end view of an arrangement such as is shown in Figure 6and illustrating how the telescopically-sliding sections may be mountedon ball bearings.

Figure 12 is an enlargement of a part of Figure 11 showing the mannerinwhichthe ball bearings may be arranged.

Figure 13 is a section on the line l3--l3 in Figure 12.

Figure 14 shows diagrammatically and by way of example one arrangementof apparatus for imparting the necessary sliding .or telescopic movementto a tubular member for the purpose of varying the effective exitdiameter or crosssectional area of the nozzle.

The type of turbo-compressor propulsive apparatus in connectionwith'which the presentinvention will be more particularly described isillustrated by way of example in Figure l and coinprises the followingprincipal features. Air is drawn in through twin intake passages A bythe impeller of a compressor enclosed in a casing B and this air isdelivered into a series of separate tubular combustion chambers 0wherein fuel is burnt. The gases from these chambers flow to and act ona turbine disposed within a casing D and on leaving the turbine thegases pass through the tubular and somewhat conical casing E to issuefrom the nozzle F with propulsive effect. Around the turbine casing Dand the jet pipe E and spaced radially out therefrom is a sleeve G andoutside this sleeve and spaced therefrom is the engine nacelle H. Thereis thus an annular space J within th sleeve through which air drawn fromthe open atmosphere through the openings 'l-l in thenac'elle H below thewings can flow along the path indicated by the curved arrows in Figure 1and constitute a lagging for the casing D and jet pipe E, and there is asimilar annular airspace K between the sleeveG and the nacelle H, but inthis arrangement air is not free to flow through this latter-spacesincethe nacelle is connected at its after end at H to the after end of thesleeve. The after-endG of the sleeve extends beyond the nozzle F-onwhich it is conveniently supported by pads G This extension of thesleeve has the efiect'of an enlargement of the diameter of the nozzle Fand as will be seen it may be arranged so that the air may flow throughthe lagging space J within the sleeve G and thus issue around the nozzleF and mingle with "the gases issuing from the nozzle.

According to this invention the extension of the sleeve G or of acorresponding part around the nozzle F made adjustable as by providingone or more separate tubular members which can slide relatively andtelescopically and thus enable the effective exit diameter of the nozzleto be enlarged or reduced as required. Such an arrangement is shown in asimple form in Figures 2 and 3. Here a single tubular section L ismounted on th end portion G of the sleeve G so that this section caneither be caused to slide outwards into the position in which it isshown in Figure 3 or moved inwards into the position in which it isshown in Figure 2. In the former and extended position the section Lhaving a diameter which is larger than that of the nozzle P will havethe effector increasing the size of the nozzle, but when the section iswithdrawn .inwards onto the end G of the sleeve the size-0f the nozzlewill be reduced to that of the nozzle itself, when the end of thetubular section L will lie with its end substantially flush with the endof the nozzle F as can be seen in Figure 2. -As will be seen the airflowing through the lagging space J will come out around the nozzle Fand serve to cool the end G of the sleev and the sliding extension L.The outer end of the tubular member L may be slightly flared as shown atL in Figure 4.

Referring to Figure .4, this shows the fixed sleeve G as carried 'bypads G on the nozzle F, but with its forward end connected atH to thenacelle H. Air can flow through the annular space K between the nacelleand the jet pipe E and issue through the annular space J around thenozzle F. The arrangement of the nacelle H may be as shown in Figure lwith openings H in its forward part (not shown in "Figure 4) throughwhich the 'air can enter.

In the arrangement shown in Figure .5 the nacelle H is connected at H"to the end of the jet pipe E or forward end of the nozzle "F so thatair cannot flow through the space between the nacelle H and the jetpipe. Air'can however flow through the space J between the fiXed'sleeVe"G and the nozzle F which carries the sleeve 'G through the pads G theair entering the space J through the annular opening J at the somewhatflared forward end'of the sleeve The air entering here can thus "flowout "betweenthe nozzle F and the tubular section L which can slidetelescopically on the fixed sleeve G Referring now to Figure "6, thisshows an arrangement in which there are two telescopically slidingtubular members L, E "the latter sliding on the tubular section L whilethis section can itself slide telescopically on the fixed sleeve '6 Thissleeve is here shown 'as mounted and 'arranged in thesame way as shownin Figure 4, being supported by pads G on the nozzle tube F andconnected at its forward end to the'nace'lle H with an interveningannular space J K through which air can flow and issue'around'the nozzleF. The tubular sections L, L can be moved separatelyand relatively tothefixed sleeve G so that they may he-either whollywithdrawn, so thatthe effective "diameter or cross-sectional area of the nozzle will bethat 'of'th nozz'le Fitself, or each section L, L may be extended so asto vary the effective exit diameter of the nozzle which will then beeither the diameter of the end of the section L or the diameter of theouter section L The effective exit diameter of the nozzle can thus beincreased in steps or otherwise as desired and by suitable determinationof the relative diameters of the telescopically sliding sections L, Lthe difference in the effective exitdiameters of the nozzle may bevaried. The tubular sections L, I. may be so mounted one on the otherthat there will be an annular space for air flow between them andbetween the inner section L and the fixed sleeve G as shown in Figs. 9,and 11.

Referring to Figures 9 and 10, these show a modified arrangement of twotelescopically sliding tubular members arranged so that when the membersare extended air may flow through the annular spaces between them, orwhen the members are withdrawn the air flow within them can be shut off.In this case the inner member L is carried on the nozzle tube F, thelatter being provided with longitudinally extending guide members Mwhich engage corresponding longitudinal guide members N within the tubeL these guide members M and N being spaced apart circumferentially andserving not only to guide the tube L as it slides on the nozzle F butalso to space it radially from the nozzle so as to leave an annular airpassage 0 around the nozzle F through which air can flow. The second andouter sliding tubular member L is similarly carried on the inner tube Lthe latter having longitudinal guide members P which engagecorresponding guide members Q within the tube L There is thus an annularair passage 0 between the tubular members L and L Air flowing throughthe annular spaces 0,0 enters through an annular opening R between theafter end of the nacelle H, which is connected to the end of the jetpipe E, and a conical casing S connected at its rearward end to the endof the sliding tube L The annular air passage R is fully open when boththe tubes L L are extended beyond the nozzle F, but if one of thesetubes is withdrawn, the size of the air inlet R will be reduced, and ifboth tubes L and L are withdrawn, as shown in Figure 10, the air inlet Rwill be wholly closed by the forward end S of the casing S coming intocontact with the after end of the nacelle H. The part S then provides acontinuous streamline surface with the contour of the nacelle H.

As an example of the manner in which the telescopically sliding tubularmembers may be mounted so as to facilitate their sliding, there may beadopted an arrangement such as shown in Figures 11, 12 and 13. In thiscase the tubes and associated parts are assumed to be asdiagrammatically indicated in Figure 6, that is to say there is a nozzleF which carries a fixed sleeve G on which in turn can slide the tube Lwhile the outer tube L can slide on the inner tube L. Since thearrangement to be described is similar as between the fixed sleeve G3and the inner sliding tube L and also between this tube and the outersliding tube L the following description will apply in each case. Ballbearings of the ladder type are employed and arranged in the mannershown in the enlarged views Figures 12 and 13. The outer tubular member,for example L carries within it a T-section guide T of which theprojecting rib lies between the lateral portions of a U-section guide Umounted on the exterior of the inner. tubular section L. Between theinterengaging parts of these guides lie two similar ball cages V. Asshown in Figure 11, there are four of these ball races between the fixedsleeve G3 and the inner sliding tube L, and similarly four races betweenthe inner sliding tube L and the outer sliding tube L all these racesbeing equally spaced apart in the circumferential direction. These racesserve to keep the tubular members concentric with the nozzle F andfacilitate the relative sliding movement of the tubes L, L Obviously ifpreferred there may be only three spaced ball races in one or each case.The guides indicated in Figures 9 and 10 and described with reference tothese figures may carry such ball races.

The sliding movement of the single or multiple telescopic tubularmembers may be effected in various ways, but a simple example of howthis may be effected is shown diagrammatically in Figure 14 inconnection with the single sleeve L. This is here assumed to be slidablymounted on a fixed sleeve in the manner shown for example in Figures 2and 3. On some adjacent fixed part such as G in Figures 2 and 3 but hereomitted for the sake of clearness, there are mounted three hydrauliccylinders W equally spaced apart circumferentially and each containing apiston W connected through a rod W to a lug L on the exterior of thesliding tube L. Two annular chambers X and Y are provided with pipingconnecting these chambers to the opposite ends of the cylinders W and tosources of supply not shown. Thus from the annular chamber X a pipe Xruns to one end of each cylinder W while from the second chamber Y apipe Y runs to the other end of each cylinder W. Thus if pressure fluid,either air or liquid, is admitted to the chamber X through a pipe X itwill flow into the inner end of each of the cylinders W and acting onthe pistons W will cause the tubular section L to be moved outwardly. Atthe same time through piping such as Y the pressure fluid can flow fromthe chamber Y and thus through the piping Y from the outer ends of thecylinders W. On the other hand if the tubular section L is to bewithdrawn, pressure fluid is admitted through the piping Y to thechamber Y and so through the piping Y to the outer ends of the cylindersW where it will act on the pistons and draw the tube L inwards. At thesame time the chamber X is placed in communication through the piping Xwith an exhaust or relief chamber.

The flow of pressure fluid to effect these movements can be controlledin some convenient manner.

The invention is particularly suitable for use where it is desirable tosupply additional fuel into the tail pipe or jet pipe E near the nozzleF. In that case one arrangement shown for example in Figures 7 and 8 maycomprise a series of fuel delivery nozzles Z disposed radially andspaced apart circumferentially, the nozzles for example being carried bythe fixed sleeve G and passing through the spacing pads G between thissleeve and the nozzle tube F within which the fuel will be deliveredfrom these nozzles into the stream of propellant gases. Each fuel nozzleZ is supplied through a separate branch Z from a common annular supplyor manifold Z disposed around the end of the nacelle I-I. Air for thecombustion of this fuel can flow through the annular space K J aroundthe nozzle F, or may be surplus air from the main jet. These figuresshow a single telescopically 7 sliding member L mounted and movable onthe fixed sleeve G What we claim as our invention and desire to secureby Letters Patent is:

l. Turbo-compressor propulsive apparatus of the type comprising acompressor, means for admitting air to said compressor and means forpassing air around said compressor, at least one combustion chamber intowhich air is delivered by the compressor and wherein fuel is burnt, aturbine driven by hot gases from the combustion chamber, the turbinebeing co-axial with and rotatably connected to the compressor to driveit, and a nozzle from which the gases which have passed through theturbine issue with propulsive effect, in combination with an adjustablesleeve surrounding and spaced from the nozzle to permit passagetherebetween of said air passed around said compressor, and means forextending the sleeve in the direction of its axis relatively to thenozzle so as to project beyond the mouth of the nozzle, the end of theprojected sleeve thereby forming the effective mouth of the nozzle,whose cross-sectional exit is correspondingly increased with consequentreduction in the velocity of the. propulsive jet.

2. Turbo-compressor propulsive apparatus of the character forth in claim1 wherein the sleeve surrounding the propulsion nozzle has an outwardlyflaring mouth.

3. Turbo-compressor propulsive apparatus of the character set forth inclaim 1 wherein the sleeve surrounding the nozzle constituted by atleast two concentric tubular parts relatively movable telescopically.

4. Turbo-compressor propulsive apparatus of the type comprising acompressor, at least one combustion chamber into which air is deliveredby the compressor and wherein fuel is burnt, a turbine driven by thegases from the combustion chamber, the turbine being coaxial With thesaid compressor to which it is connected and whereby the compressor isdriven, and a nozzle from which the gases which have passed through theturbine issue with propulsive effect, in combination with an adjustablesleeve surrounding and spaced from the nozzle and constituted by atleast two concentric tubular parts relatively movable telescopically,and means for sliding the parts of the sleeve relatively and causing apart of the sleeve to project beyond the nozzle and thereby increase thecross-sectional exit area of the mouth O-f the nozzle.

FRANK BERNARD HALFORD.

ERIC STANLEY MOULT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 719,849 Oberwalder Feb. 3, 1903 1,140,259 Elliott. et al..Wiay 18, 1915 2,102,559 Kadenacy Dec. 14, 1937 2,402,363 Bradbury June18, 1946 2,408,099 Sherman Sept. 24, 1946 2,418,488 Thompson Apr. 8 19472,487,588 Price Nov. 8, 1949 2,501,633 Price Mar. 21, 1950 2,503,006Stalker Apr. 4, 1950 FOREIGN PATENTS Number Country Date 82,468 FranceDec. 7, 1868 577,949 Great Britain June 6, 1946

